1.  9. Determine the heat of reaction for the combustion of ammonia, 4NH_{3}(g) + 7O_{2}(g) → 4NO_{2}(g) + 6H_{2}O(l) using molar enthalpies of formation. NH3(g) –45.9 NO2(g) +33.1 H2O(l) –285.8 
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2.  13. For the reaction below, if the rate of appearance of Br_{2} is 0.180 mol/L·s, what is the rate of disappearance of NOBr? 2NOBr(g) → 2NO(g) + Br_{2}(g) 
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3.  12. The rate of reaction for the formation of carbon monoxide is measured at 1.24 mol/L·hr. What is the rate of formation of carbon monoxide in units of mol/L·s? CH_{3}CHO(g) → CH_{4}(g) + CO(g) 
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4. 
Use the equilibrium constants for the following reactions at 700 ^{0}C

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5.  25. Write a balanced chemical equation which corresponds to the following equilibrium constant expression. 
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6.  11. For the reaction below relate the rate of disappearance of hydrogen to the rate of formation of ammonia. N_{2}(g) + 3H_{2}(g) → 2NH_{3}(g) 
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7. 
Calcium carbonate decomposes to calcium oxide and carbon dioxide.

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8.  10. The standard molar enthalpy of formation of NH_{3}(g) is –45.9 kJ/mol. What is the enthalpy change if 9.51 g N_{2}(g) and 1.96 g H_{2}(g) react to produce NH_{3}(g)? 
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9.  . Nitrosyl chloride decomposes according to the chemical equation below. 2NOCl(g) 2NO(g) + Cl_{2}(g) A pressure of 0.320 atm of nitrosyl chloride is sealed in a flask and allowed to reach equilibrium. If 22.6% of the NOCl decomposes, what is the equilibrium constant for the reaction? 
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10.  4. When 66.0 g of an unknown metal at 28.5^{0}C is placed in 83.0 g H_{2}O at 78.5^{0}C, the water temperature decreases to 75.9^{0}C. What is the specific heat capacity of the metal? The specific heat capacity of water is 4.184 J/g^{0}C. 
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11.  8. All of the following statements are true EXCEPT 
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12.  17. The rate constant of a firstorder decomposition reaction is 0.0147 s^{–1}. If the initial concentration of reactant is 0.178 M, what is the concentration of reactant after 30.0 seconds? 
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13.  18. The rate constant for the decomposition of cyclobutane is 2.08 × 10^{2} s^{1} at high temperatures. C_{4}H_{8}(g) → 2C_{2}H_{4}(g) How many seconds are required for an initial concentration of 0.100 M C_{4}H_{8}(g) to decrease to 0.0450 M? 
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14.  6. When 10.0 g KOH is dissolved in 100.0 g of water in a coffeecup calorimeter, the temperature rises from 25.18 ^{0}C to 47.53 ^{0}C. What is the enthalpy change per gram of KOH dissolved in the water? Assume that the solution has a specific heat capacity of 4.18 J/g^{0}C. 
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15. 
16. The initial rates method was used to study the reaction below.
2A + B + C → D + E

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20. For the firstorder reaction below, the concentration of product B after 24.2 seconds is 0.322 M. If k = 8.75 × 10^{2} s^{1}, what was the initial concentration of A?

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17.  7. 10.0 g of ice at 0.00 ^{0}C is mixed with 25.0 g of water at 35.00^{0}C in a coffeecup calorimeter. What is the final temperature of the mixture? The specific heat of water is 4.18 J/g ^{0}C; the heat of fusion of water is 333 J/g. 
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18.  3. Water has a specific heat of 4.18 J/g · ^{0}C. If 35.0 g of water at 98.8 ^{0}C loses 4.94 kJ of heat, what is the final temperature of the water? 
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19.  The initial rates method was used to study the reaction below. A + 3B =2C [A] (mol/L) [B] (mol/L) D[A]/Dt (mol/L×s) 0.210 0.150 3.41 x 10^3 0.210 0.300 1.36 x 10^2 0.420 0.300 2.73 x 10^2 
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21. For the secondorder reaction below, the rate constant of the reaction is 9.4 × 10^{–3} M^{–1}s^{–1}. How long (in seconds) is required to decrease the concentration of A from 2.16 M to 0.40 M?

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21.  Which of the following statements is/are CORRECT? 1. Product concentrations appear in the numerator of an equilibrium constant expression. 2. A reaction favors the formation of products if K >> 1. 3. Stoichiometric coefficients are used as exponents in an equilibrium constant expression. 
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22.  29. Which of the following may change the ratio of products to reactants in an equilibrium mixture for a chemical reaction involving gaseous species? 1. Increasing the temperature. 2. Adding a catalyst. 3. Adding gaseous reactants. 
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23.  2. If 495 J is required to change the temperature of 12.7 g of sodium chloride from 75.0^{0}C to 135 ^{0}C, what is the specific heat of sodium chloride? 
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24.  5. A coffeecup calorimeter contains 10.0 g of water at 59.00^{0}C. If 3.00 g gold at 15.20 ^{0}C is placed in the calorimeter, what is the final temperature of the water in the calorimeter? The specific heat of water is 4.18 J/g ·^{0}C; the specific heat of gold is 0.128 J/g ·^{0}C. 
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25.  What is the correct equilibrium constant expression for the following reaction? CO_{2}(g) + 2H_{2}O(g) CH_{4}(g) + 2O_{2}(g) a. b. c. d. 
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26.  1. If 50.0 g of benzene, C_{6}H_{6}, at 25.0^{0}C absorbs 2.71 kJ of energy in the form of heat, what is the final temperature of the benzene? The specific heat of benzene is 1.72 J/g·^{0}C. 
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27.  28. For the system CO(g) + H_{2}O(g) CO_{2}(g) + H_{2}(g) K is 1.6 at 900 K. If 0.400 atm CO(g) and 0.400 atm H_{2}O(g) are combined in a sealed flask, what is the equilibrium partial pressure of CO_{2}(g)? 
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28.  19. The reaction A → B follows firstorder kinetics with a halflife of 21.7 hours. If the concentration of A is 0.023 M after 48.0 hours, what is the initial concentration of A? 
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29. 
22. For the firstorder reaction below, the initial concentration of A is 0.80 M. What is the halflife of the reaction if the concentration of A decreases to 0.10 M in 54 seconds?

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30.  14. Dinitrogen pentaoxide decomposes to nitrogen dioxide and oxygen according to the following balanced chemical equation and rate expression. 2N_{2}O_{5}(g) → 4NO_{2}(g) + O_{2}(g) rate = k[N_{2}O_{5}] What is the overall reaction order? 
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